3Z Series — Three-column vertical reciprocating acetylene compressor. The additional third cylinder column delivers 200–270 Nm³/h at 2.5 MPa, making the 3Z the preferred machine for medium-to-large dissolved acetylene filling plants in Russia and the CIS.

Product Overview: 3Z Series Acetylene Compressor

The 3Z series acetylene compressor is a three-column vertical (Z-type) reciprocating piston compressor for dissolved acetylene production in medium-to-large cylinder filling plants. The 3Z designation identifies the three-cylinder configuration: one dedicated low-pressure stage cylinder and two high-pressure stage cylinders arranged vertically on a common crankshaft. By adding a third cylinder column to the two-column architecture of the 2Z series, the 3Z achieves a 35% increase in throughput — from 200 Nm³/h (2Z-3.34/25) to 270 Nm³/h (3Z-4.5/25) — within the same Z-type vertical frame and within the same plant floor area envelope.

The three-column configuration also improves the dynamic balance of the machine compared to the two-column 2Z design. With two high-pressure stage pistons sharing the compression load, the peak force on any single crank throw is reduced, which lowers vibration transmitted to the foundation and extends the service life of crankshaft bearings and connecting rods under the sustained high-cycle loading of continuous production operations.

All safety requirements that apply to the 2Z series apply without modification to the 3Z: oil-free cylinder design using PTFE piston rings and packing, water cooling of all hot surfaces including cylinder jackets, the interstage cooler, and the aftercooler, ATEX Zone 1 Group IIC explosion-proof electrical equipment throughout, and copper-free materials in every wetted component. The 3Z series is manufactured at our production facility in Russia to GOST-R and GOST 5457 requirements, with full Rostechnadzor registration documentation provided as standard for the Russian and CIS market.

Applications: Dissolved acetylene cylinder filling plants with daily output of 300–600 cylinders per shift, larger oxy-acetylene welding gas supply operations, acetylene gas recovery systems in chemical plants, and acetylene feed compression for chemical synthesis including BDO, vinyl acetylene, and acetaldehyde production.

3Z Series vs. 2Z Series: When to Choose Three Columns

The decision between the 2Z and 3Z series is determined primarily by the required cylinder output and the acetylene generator capacity of the plant. The following comparison assists in selecting the correct series for a new plant or a capacity expansion.

Technical Specifications — 3Z Series Acetylene Compressor

Both 3Z models share the same three-column belt-drive vertical frame. The model number encodes the flow capacity: 3Z-3.34/25 delivers 3.34 Nm³/min (200 Nm³/h) and 3Z-4.5/25 delivers 4.5 Nm³/min (270 Nm³/h) at 2.5 MPa discharge pressure.

Note: Flow rates are stated at standard conditions (0°C, 0.101325 MPa). Discharge pressure 2.50 MPa is the standard for dissolved acetylene cylinder filling per GOST 5457 and equivalent international standards. Custom configurations for chemical synthesis and process gas duties at different pressures and flows are available on request.

General Series Parameters

Why Three Columns: The Engineering Rationale

Splitting the High-Pressure Load

In a two-stage acetylene compressor, the high-pressure stage is where the greatest mechanical stress concentrates: the piston, piston rod, connecting rod, and crankpin all bear the maximum force at top dead centre of the HP stroke. In the two-column 2Z series, a single HP cylinder handles the entire second-stage compression load. In the three-column 3Z series, two HP cylinders share this load — each handling half the HP gas flow. This arrangement reduces the peak rod load on each individual HP cylinder by approximately 50% compared to a single HP cylinder handling the same total flow. The result is lower stress on HP cylinder components, longer service life of HP piston rings and valves, and reduced vibration from the HP stroke impulse.

The Role of Belt Drive in Three-Column Configuration

The 3Z series uses belt drive as standard rather than the direct-drive option available on some 2Z models. The belt-drive configuration serves two important functions in the three-column machine: first, the pulley ratio can be adjusted to change the compressor speed without modifying the motor, allowing the output to be matched to different acetylene generator capacities without electrical changes. Second, the belt provides a degree of mechanical isolation between the motor and the crankshaft, absorbing torsional shock loads that would otherwise be transmitted directly to the motor bearings during start-up and load transients. For a machine running continuously at the high-cycle rates required in a production filling plant, this isolation extends motor service life under realistic operating conditions.

Capacity Economics: One 3Z vs. Two 2Z Units

For a plant requiring 200–270 Nm³/h of acetylene compression, the alternative to a single 3Z unit is two parallel 2Z units (e.g. two 2Z-3.34/25 machines at 200 Nm³/h each, running one fully loaded and one at reduced load). While the two-2Z arrangement provides redundancy, it requires twice the cooling water connections, twice the ATEX electrical panels, twice the maintenance scope, and approximately 40–60% more floor area. For plants with a single production shift and no requirement for standby redundancy, the single 3Z unit provides the required throughput at significantly lower total installed cost and ongoing maintenance expense. For plants requiring 24-hour operation with no planned downtime, two 2Z units in parallel — one duty, one standby — remains the preferable configuration.

Working Principle and Structural Composition

The 3Z series operates on the reciprocating piston principle with a three-column vertical Z-type frame. The belt-driven crankshaft converts the motor’s rotational motion into the upward and downward reciprocating motion of three vertical pistons. The first-stage (low-pressure) piston draws purified acetylene from the generator at near-atmospheric pressure and compresses it to the interstage pressure of approximately 0.6–0.8 MPa. After passing through the interstage cooler (maintaining temperature below 100°C), the gas splits equally into two second-stage (high-pressure) cylinders, each of which compresses the gas from interstage pressure to the final discharge pressure of 2.5 MPa. The discharge flows from both HP cylinders recombine and pass through the aftercooler to deliver acetylene below 80°C to the filling manifold.

Key Structural Components and Safety Features

Core Advantages of the 3Z Series

Material Specifications for Acetylene Service

Selection Guide: When to Specify the 3Z Series

3Z Series vs. Alternatives: Objective Comparison

Factory acceptance test — every 3Z unit is mechanically tested at design conditions with all three cylinders operating, and all automatic safety shutdown functions are simulated and verified before shipment

Frequently Asked Questions — 3Z Series Acetylene Compressor

Request a Technical Proposal for Your Acetylene Plant

Our engineering team has over 70 years of experience manufacturing acetylene compressors for dissolved acetylene plants across Russia and the CIS. Whether you are expanding an existing 2Z-equipped plant or specifying a new medium-to-large facility from the ground up, the 3Z series acetylene compressor delivers the throughput increase your plant needs in a single machine with complete GOST-R, GOST 5457, and Rostechnadzor compliance documentation as standard.